Somewhere way back in your training, you were probably introduced to the Incident Pit. It’s a fairly dramatic diagram with the words “fatal” and “death” appearing at the bottom. The concept was meant to inspire you to deal with problems early, keep control and stay safe, with the tag line “Don’t fall in.” This always seemed to be a slightly strange thing to say to divers, who are destined to fall in (to a body of water) quite deliberately. Other than encouraging you to run through your own personal risk assessment for a dive, that’s about all the standard training material has to say about pre-dive thinking.
In many sports the technique of visualisation is used to help elite athletes achieve their potential, and there’s good evidence that it works at lower levels too. Visualisation is the process of creating a mental image of what you want to happen or feel in reality. An athlete could use this technique to picture crossing the finishing line first. For a diver there is clear potential to visualise a relaxed, in control dive and achieve a state of calm and well-being before a dive. In fact, most people naturally tend to think through and rehearse what’s about to happen to them. So quite possibly you have started to think this way already.
Sometimes these preparatory thoughts can be plagued with recurring images of past mistakes or near misses, and that’s not conducive to ensuring the success of the upcoming dive. It can be more helpful to actively direct your pre-dive thoughts and control those images in your head. And the visualisation probably needs to be more than just a visual experience. To really be successful, you would need to focus on all the senses; the rush of cold water, the smell of the sea, the feeling of pressure on your legs as you enter the water, the sound of your bubbles.
When you visualise the successful dive, you are stimulating the same regions of your brain as you do when you physically perform the same action. So, thinking the dive through, with all it’s stages, is a way of conditioning your brain for a successful outcome. Perhaps the visualisation starts before the dive, right back to the preparing your equipment. And the beauty of this preparation is that you could be doing it anywhere. Picture being on the bus thinking about packing your kit for the weekend.
What if we extend this to thinking through the different situations that may arise underwater? Rather than the scary prospect of the Incident Pit, why not challenge divers to visualise their response to common problems? What would they do if their torch fails on a night dive? It’s too easy to just say “I’d get my back up torch out”. In order to visualise it you would have to work through being able to open your BCD pocket (feel the zipper in your hand, hear the zip and feel as it bumps along the teeth), feel through the gloves for the piston clip, unclip the torch lanyard from the D ring, feel the lanyard in your hand etc. Which pocket? What else in in there to avoid dislodging? How will the torch feel in my hand? This is a far more powerful psychological technique than a glib “Get my back up” response.
For divers just starting out on their diving journey, visualisation can be an excellent way to deal with the nervous trainee. Try to remember the first time you put all your dive kit on. How tight did your neck seal feel? How restricted was your movement? These are things we all take for granted now. We have done it often enough that we barely register the sensation. I think there is a real value in talking through that first dive. This is not part of your SEEDS brief, this is so much more. Find a quiet space, sit down and step your way through the dive, start building the neuronal connections in a positive way and help boost performance.
It doesn’t matter how carefully you monitor your fluid intake before a dive, or how close to dive time you leave the last toilet visit, we have all got out from a dive ready to rugby tackle anyone standing between us and the toilet. It’s well known that going for a dive causes an increased need to urinate. There are some interesting physiological changes that come to play. Immersion and temperature changes cause a narrowing of the blood vessels in the extremities. This results in an increased volume of blood to the central organs which is interpreted by the body as fluid overload. This causes the production of antidiuretic hormone (ADH) to stop, signalling to your kidneys that they need to produce urine to lower the blood volume. So even if your last toilet visit was only minutes ago, you can quickly find yourself feeling the need to go again.
It’s almost impossible to give an exact measurement for the volume of the human bladder as everyone’s ability to hold urine varies. Normal adult bladders hold between 300 and 400ml but can hold up to 600 or even 1000ml in some cases. The need to urinate is stimulated by the expansion of the bladder which triggers the Micturition reflex centre in the spinal cord. Most adults will feel the need to urinate when their bladder is only around a quarter to a third of its normal capacity. In normal circumstances, adults will feel the need to empty their bladder about every 3 hours, but as divers we know the effect that immersion plays.
There’s always a big debate in the wetsuit diving community about whether peeing in a wetsuit is acceptable or not. In a drysuit, the debate becomes somewhat redundant unless you have a P-valve fitted. But is there any danger to ‘holding it in’? When you first feel the need to pee, your bladder probably has quite a way to go before it’s completely full. As your bladder fills up the muscles around it will contract to keep urine from leaking out until you’re ready – just make sure you can get out of your suit fast enough!
The dangers of holding your pee are mostly cumulative, so the occasional episode probably isn’t harmful. However, if you are diving frequently and often find yourself ignoring the need to pee you run the risk of urinary tract infections, urinary retention (the muscles can’t relax even when you want to pee) or bladder atrophy (leading to incontinence). But for most people, you can hold your bladder full for a few hours without serious complications, even though its uncomfortable.
If you dive in a wetsuit, you can of course make the call as to whether you pee in your suit or not. The old saying is that 50% of divers pee in their wetsuits and the other 50% are liars. So whichever camp you fall into, just make sure you flush your suit through before you get out of the water and start to take it off, and please wash your suit thoroughly between dives. If you’re a drysuit diver, there’s always the option of adult nappies to ensure that you can relieve yourself. If that seems a little retrograde, or as you march middle age a little too prophetic, then perhaps a P-valve is an option.
Not surprisingly there are hazards associated with P-valves too. Ignoring the issues with getting a stick-on condom or the female cup attached successfully, so that the urine does actually enter the tubing to leave suit, there are reported cases of urinary sepsis. The tubing used to connect the urine to the P-valve is the ideal breeding ground for Pseudomonas bacteria, and it only takes a small amount of backward flow to introduce those bacteria into the body. If you think rinsing your wetsuit is a bit of a faff, syringing antiseptic through P-valve tubing should give you some perspective.
In the depths of winter, there are two major factors that reduce diving time, low pressure weather systems and snot. As the air becomes colder and drier, the cells lining the nasal cavity have to work quite hard to warm and moisten the air that we breathe in. The cells producing the mucus are called goblet cells (which is a reference to their shape, not an instruction for what to do with the mucus). The mucus itself is a mix of proteins which contribute to the protective role in a number of ways; enzymes that can attack bacterial cell walls, antibodies to bind to pathogens and lactoferrin to mop up any free iron.
But the real star of the snot show is Mucin, a group of large proteins with lots of sugar molecules bound to the central regions of the molecule. These sugars are important as they allow the Mucins to have gel-like properties with an amazing water holding capacity. Aggregations of Mucin molecules are secreted by the cells lining the airways (and digestive tract too) and the sugar coating helps them to resist digestion. Over 20 human Mucin genes have been identified and the proteins that they produce help bind pathogens together, and are one of the reasons why you will make more snot when combatting a nasal infection.
It’s not just humans and other mammals that can make Mucin, a similar group of proteins is found in the most humble gastropods. We are all familiar with snail trails. (I’m sure that was my Nan’s phrase for a small child with streams of nasal mucus running down their top lip!) Snails move using a combination of their muscular foot and a lubricating slime. Now here’s where it starts to get strange, mollusc slime is a non-Newtonian fluid. It doesn’t follow the normal rules that govern viscosity in fluids, but rather changes as stress is applied to it. This explains why the same mucus can be used to allow snails to move and to bind to a surface. As the wave of contraction from the muscular foot of the snail acts on the sticky slime, the slime changes to become a free-flowing liquid. When the pressure is removed, the slime becomes gel-like again, allowing snails to lodge in overhangs and defy gravity.
For marine snails, it’s slightly harder to see the need for a lubricant, but it turns out that the slime trail for some species has even more functions. It’s a big commitment for some species to make a slime trail, estimated at up to 60% of their total energy use. Periwinkles will sniff out and follow fresh trails made by other molluscs to reduce this energy requirement. Mucus trails bind microalgae from the water when they are fresh and so they can be an excellent food source. Yep, that’s right, eating the algae from someone else’s snot trail is a good thing for Periwinkles, but please don’t try this at home!
Limpets are grazing feeders who return to their ‘home-scar’ on the rock every time the tide goes out. For them, the mucus trail is their route to find the carefully etched out rock into which their shell can clamp down to protect them from predators, sealed with a mucus layer to prevent them drying out. Not so much “Follow the yellow brick road” as “Follow the limpet snot trail” to get home. With the right conditions, you can see limpet snot trails on rocks as the tide falls.
For some molluscs, their slime trail is also important for mating. Chemical signals indicate the sex of the snail, allowing prospective mates to find and copulate. Male periwinkles can track down a female by following chemical markers in the slime. But the females of one species of periwinkle (Littorina saxatilis) turns off this signal to avoid mating. L.saxatilis live in dense colonies and like other periwinkles will mate up to 20 times a day throughout the year. This seems like a strange strategy for any species to survive, the general rule being that males mate as often as possible, whereas females try to be selective about mates.
Why would female L.saxatilis try to avoid mating? Males mount onto their mate and crawl around to the lip of the shell. This means that the female is then bearing the load of adhering both parties to the rock, and remember that our slime is non-Newtonian, more stress makes it flow. Having a male periwinkle on your back will double the stress and can result in both parties being swept off the safety of the rockline. For females, mating will increase their chances of being predated upon. So the female L.saxatilis turns off the sex signal in her slime. Males will still follow the slime trails, but it’s a 50:50 chance that they could be trying to mate with another male at the end of the journey.
Since Ancient Greece snail slime has been used in cosmetics. It contains high levels of hyaluronan which is a major component of the proteins that support our cells. It is freely available as a cosmetic claimed to promote the formation of collagen and help to improve skin structure. More seriously, hyaluronan is gaining popularity as a biomaterial scaffold which is helping the next generation of bioengineers to promote the formation of blood vessels in tissue engineering. Something to ponder when you are relegated to shore cover as you are too snotty to dive…
July 1969 is best remembered in popular culture for the Apollo 11 moon landings and Neil Armstrong’s declaration of “..a giant leap for mankind.” But at the same moments as the world was transfixed by NASA’s reports, another equally challenging expedition was underway off the North American coastline. Six men on board the Ben Franklin drifted for 30 days in the currents of the Gulf Stream, using very little power apart from their floodlights.
The Gulf Stream project grew out of earlier bathyscaph explorations. Bathys means deep and skaphe means light boat. Bathyscaph expeditions were designed to explore the depths, to plummet to the sea bed, make observations and then return to the surface. During the 1950s successful dives were made into the Marianas Trench at a depth of over 10,000 metres.
The Ben Franklin was different, she was a mesoscaph, meso meaning middle, and her design reflected that idea. The Ben Franklin was designed to be a light vessel using modern steel and Plexiglas to ensure that in the event of any problem, she could always return to the surface. Whereas launching bathyscaph required considerable winch power and large support vessels, mesoscaphs were expected to operate in shallower waters, with minimal surface support.
It took Jacques Piccard, a Swiss oceanologist (and no relation to Jean-Luc) nearly a decade to design and build the Ben Franklin. Jacques father, Dr Auguste Piccard was himself an ocean explorer who designed bathyscaphs and it was his discussions with Jacques that initiated the mesoscaph project. The design was a cylindrical cabin capable of holding the crew, with 400kg of Lithium hydroxide in panels to absorb the carbon dioxide, over 1100 kg of silica gel to absorb the water and reduce humidity, 250 kg of liquid oxygen and enough dehydrated food to last for 30 days. Piccard orginally envisaged the interior being lined with mahogany, to emulate a fine yacht, but was overridden and the internal structure was clinical and white.
Setting out from Florida, there was no big fanfare or press launch. The initial plan was to see if they could last 3 days and then make a decision over whether to continue. So on 14th July 1969 the Ben Franklin was towed into position and at 20.34 the hatch was closed. The crew descended initially to the bottom of the sea and then rose slightly controlling their descent by ditching ballast weight or adding air to ballast tanks. Over the next 30 days they would drift for 2800 km at speeds between 0.2 and 3 knots. They experienced internal waves within the Gulf Stream that would cause their depth to oscillate by over 100 metres, although the rate of rise didn’t concern the crew. They established that there was perceptible daylight at 600 metres and conducted a series of acoustic measurements using explosions set off from two surface support vessels.
On board for the trip was an observer from NASA, whose primary function was to look at the interaction between the crew. 50 years ago NASA was already considering the International Space Station and longer voyages to Mars. The Gulf Stream project provided an ideal test bed to study sleep patterns which deteriorated after the first 3 weeks and eating arrangements, as crew members chose to eat alone rather than together. Bacterial contamination, firstly of the cold water supply and then of the walls and floors would have posed a serious threat to the crew had the experiment continued beyond 30 days. Even an increase in the cleaning regime failed to stem the growth of bacteria.
Communications between the Ben Franklin and the surface support vessel the Privateer take place using an acoustic telephone, and the recordings made by the NASA observer show that the stress levels of the crew rose enormously at times when communications were restricted by weather or surface vessels deviating their course due to other ships. On 24th July 1969 as the crew of Apollo 11 splashdown into the ocean, the crew of the Ben Franklin are experiencing a temperature of 14 degrees and tumultuous seas as the internal waves catch the vessel. It wasn’t until 14th August that they surfaced and at 8.09 the hatch was opened. They were due east of Baltimore and the US Coastguard vessel Cook Inlet was there to rendezvous with them. A week later the Ben Franklin had been towed into New York for a hero’s welcome. A remarkable tale of human endeavour had come to an end, but in a world transfixed by the moon it was barely noticed.
Once upon a time my Editor and I went diving together. It was a few weeks after he had penned an opinion that back entry dry suits were an integral part of the buddy relationship. It was, he opined, important to trust your dive buddy to close the ridiculously expensive brass zip without trapping your undersuit or that annoying flappy bit of neoprene stuck in the back of several suits. Relying on your buddy to ensure the zip was closed all the way, contributed to the mutual support aim of buddy diving. As we stood kitting up for our dive, I happily fastened my front-entry plastic zip with the minimum of fuss and decided to tackle Simon about his ill thought-out piece.
I have a front entry suit because I like being responsible for myself…or more precisely I don’t always trust my buddies, especially if my buddy is a trainee or new to dry suit diving. I lack the ability to rotate my neck like a barn owl to check that everything is OK behind me. It only takes one trainee, who earnestly assures you that the zip is closed when in fact it’s half an inch open, to make you reconsider. When that cold rush of sea water starts running down your shoulder, you know that this is one mistake you won’t be making again!
But how do you get the dive manager or boat crew to double check your zip without offending your buddy? Surreptitiously sidle over to the crew as you leave harbour, keep your voice low so it can barely be heard above the engines (and definitely not by your buddy) and assume some wistful position that doesn’t look like you’re hugging a large imaginary tree? And of course all the while you must try not to offend your buddy and generate “trust issues” because at the very first time you are supposed to rely on their assistance you bailed and found another source of help.
So for me a front entry suit solves all of these problems. If my zip isn’t closed properly, then that’s my fault and my soggy right leg. For anyone thinking of getting a suit with a plastic dry zip, they are fabulous but never ignore the need for silicon greasing the stop end, even between dives if you’ve peeled out of your suit. But it’s my responsibility and I’m good with that.
Front entry suits frequently have two zips, the dry one and a cover zip, and this can cause endless problems too. I took my eye off the ball one day whilst doing a dry suit introduction in the pool. I will accept some of the blame, but we had just done a session at the dive centre trying on suits, and the concept of a dry zip and a cover zip had been discussed as we established that this particular suit was a good fit. I am to blame for thinking that our discussion would be remembered barely an hour later when we kitted up on poolside. When I turned to look at my two eager divers, they had closed their zips and were ready for the stride entry. Yes, the cover zip was closed. No, the dry zip wasn’t. Yes, the suit filled with water (luckily the warm pool version). No, the diver couldn’t climb up the pool ladder unaided. The phrase “I seem to be getting a little wet” was a total understatement on her part. Once dekitted, we laid the unfortunate lady down and rolled her around on the pool surround to empty the water. To give her credit she laughed nearly as much as we did and gamely carried on the orientation session. Five years on she is still diving, in a front entry suit, which she knows has two zips and one of them is very important.
Sadly she’s not the only one who’s been caught out in this way. Even some quite experienced visiting divers have missed the ‘hard to do up’ brass zip and relied on the ‘easy to do up’ cover zip in one of our rental suits. A cold shot of Irish Sea water down the leg is a salutary lesson in the need to familiarise yourself with hired equipment. So for anyone who read, noticed and remembered Simon’s treatise on the importance of back zipped suits for buddy trust and diving, maybe I was wrong to criticise him and perhaps divers with front entry zips could do with their buddy’s assistance, just sometimes.
We rely on our diving buddies not only to share the safe diving we are all seeking, but to provide the support to take on more challenging dives and the back-up when things go wrong. Members of other sports don’t have to rely on each other in anything like the same way. Poor teamwork on a football pitch means you lose the match, but no-one’s life would be endangered by it. Poor teamwork on a dive trip means oxygen cylinders don’t get checked, dive briefs get skipped and the outcomes can be deadly serious. With strong dependency on the people in our dive centre can come strong emotions. Longstanding members of a club will know each other’s families, children will spend their summer holidays on dive trips and learn to snorkel or dive within the branch. Non-diving partners can frequently be found supervising a game of beach cricket for a coach load of divers’ children. So woe-betide any Johnny-come-lately who suggests that, instead of the annual pilgrimage to Weymouth, they would like to head to the Farne Islands this year. You are not suggesting that diving with seals might be a fun trip. Oh no! You are (inadvertently) criticising years of family summer holiday tradition! How very dare you?
Diving attracts people from a wide range of day jobs and with that diverse background comes a wide range of skills. The key thing for all of us is the ability to work within the team, to respect each other’s perspective, to negotiate change and to keep an open mind. The job of a dive instructor may seem simple but really good instructors will have a skill set that would make a recruitment agency go weak at the knees. Some time ago a study tried to calculate the value of a mother, checking all her many roles and pricing the commercial equivalent. The final figure was somewhere over £100,000 a year. Putting a value on your dive centre manager will reveal a similar scary figure. Can you imagine employing someone to check the training, observe instructors, meet and greet, strategically plan, keep tabs on the kit and manage the members within the club? For those frustrated members within clubs please note I specifically said putting a value on your DO, not a price! Dive clubs can be the most frustrating places in the world at times – but they can also be the most rewarding and supportive environments for your dive adventures.
Choose yours wisely.
Love is in the air. As divers we obviously prefer our air to be uncontaminated in anyway, but the reality is that many of us will meet our partners/spouses/significant others through our dive club, or on a course somewhere, or hanging around a dive boat. There’s an honesty that comes with having a diving partner. They already know about the hideously early starts to get to the slack water window on a dive site. They understand the stress when your weekend trip is looming and you still haven’t managed to get to the dive shop for an air fill. They are happy to abandon any idea that the garage will ever accommodate the car again as your collection of dive kit expands to fill the available space. They know that you will finish your dive with hair resembling a bird’s nest and a smear of snot across your face. And they won’t think any less of you for any of it.
In fact there is something evolutionarily positive about partnering up with another diver. You’ve got a basic health screen for starters. And there’s a reasonable level of physical fitness. The ability to carry a 15 litre cylinder is a fine test for being able to carry the shopping in from the car or a laundry basket of wet washing. Divers generally have a level of practical skills useful enough for most DIY. And any Dive Leader who has successfully buddied a nervous, newly-qualified diver will have people skills to deal with most situations in life.
I once took a diver out in Cyprus on a nice easy shore dive, but the slight swell running made getting back to shore one of those nauseating moments where the seaweed and us were moving in harmony but the seabed was doing its own thing. This was too much for my nervous trainee who signalled and headed up. We ascended together and on the surface she spat her reg out before she’d inflated her BCD. Getting a firm grip on her, I reached for her inflator and hit the button. My reward was a face full of vomit as her seasickness overtook her. Never have I been so grateful for my mask and regulator. But what excellent training for parenthood! Anyone who has ever reared children will appreciate the desire to run away and get some SCUBA kit before changing an explosive nappy. Even if your conscience overcomes you and you decide to stay with the baby, at least your breath hold techniques will come in very handy.
If your partner is not a diver then you will have to maintain the mystical air of the ‘deep sea diver’. For non-divers our world can be a strange and confusing place, and their concepts of divers will be guided by Sean Connery as James Bond stepping out of a dry suit in Goldfinger. His dinner jacket was immaculate. I tried this once for a film themed fancy dress party. I persuaded my dad to lend me his dinner jacket and dressed out of the back of the car, cunningly parked only 20 yards around the corner. Fully suited with my dive kit on I walked to the front door and rang the bell. It was July and by the time I had made my grand entrance perhaps 20 minutes had passed. My pièce de résistance was to open my drysuit and step out. And there I stood, in the crumpled, creased, soggy mess formally known as my dad’s dinner suit. It was an entrance alright. While paying the extortionate dry cleaning bill, I reflected on how the media portrays diving as such a glamorous sport and how we have a responsibility to keep that alive for our non-diving friends and relations.
It’s only when we persuade the non-divers to come and try a SCUBA session that they will really understand what we’re up to and if we are lucky they may well be hooked too. It’s possible to get married underwater in a number of places in the world. Instead of saying “I do”, you can exchange “OK” signs and then go for the first kiss. It won’t be a long, passionate, drawn-out snog! But it will hopefully be the start of sharing life’s adventure with your buddy. At least you should reduce the number of guests to something manageable as you can limit invites to qualified divers. Why not score extra points with your dive buddies and make it a club trip? After all you’re a diver – you can take the pressure! Happy Valentine’s Day.
Michelle has been scuba diving for nearly 30 years. Drawing on her science background she tackles some bits of marine science. and sometimes has a sideways glance at the people and events that she encounters in the diving world.